This invention relates to electrical wiring devices and particularly to unitary receptacles having multiple, especially four, outlets.
Receptacles with two outlets are commonly used for receiving the plugs of two appliances. In certain instances it is desirable to provide a receptacle with more than two outlets to reduce the installation time. The present invention is particularly directed to a receptacle having four outlets such as for office lighting applications where it would be normally installed in a ceiling recess fixture, such as an outlet box or concrete ring, and permits four fixtures to be plugged in at one receptacle location. The receptacle is designed in one embodiment to have a shallow body of molded insulating material with an integral mounting flange at the rear edges of the body so the receptacle does no extend into the recess fixture, thus requiring less recess volume. In other forms of the invention, the mounting flange may be located forwardly of the rear edges of the shallow body so the body extends within the recess fixture. Internal contact elements of the four outlets are located within the housing portion of the body and the front face has plug blade receiving apertures for communicating with the internal contact elements. A rear closing plate of insulating material is configured to fit within the back edge of the housing portion substantially flush with the mounting flange and provides a substantially planar rear surface for the entire unit.
The internal contacts extend forwardly from first and second conductive plates that rest within the housing. A first conductive plate is configured as a ring and is located near the periphery of the unit while the second conductive plate is configured to fit within the aperture of the first plate and can be made from the same piece of starting material as the first plate. Each plate supports a contact element for each of the four receptacles that is aligned with a plug aperture in the front face. For a grounding receptacle, as is frequently desired, a third group of the internal contact elements is included that is attached to a third conductive plate that is located on the outside, rearward, surface of the closing plate and extends through apertures within the closing plate.
An additional feature of the invention is that the ring-shaped conductive plate is provided with means for readily separating it into two separate plate portions, such as by a break-off element that can be easily severed by an installer so each plate portion has contact elements for two outlets only. The purpose in doing so is for connection to a multiwire circuit or to permit the switching of two outlets while the other two outlets are always energized. The break-off portion is accessible through an opening in the rear closing plate so disassembly is not required in order to use it.
The unit achieves compactness as well as economy in the use of material. One example of this is that the smaller line terminal plate is blanked from the scrap inside of the larger of the two conductive plates and the two plates are disposed in the unit in a common plane that contributes to the shallowness of the design.
Another aspect of the invention is that the four outlets are oriented, by the configuration of the internal contacts and the plug receiving apertures, so that four angle plugs having line cords coming out parallel to the front face of the receptacle can be used without interfering with each other. This is done by having the pattern such that each plug and cord extends away from the receptacle in one of four orthogonal directions and none of the cords needs to pass over any of the other cords or plugs. In contrast, with a normal duplex receptacle, the outlet configuration is such that each plug pattern requires the use of a plug that causes the line cord to extend away from the receptacle in the same direction and angle plugs cannot be used. With the invention, better appearance is achieved by having no drooping cords and also by having cords extend in different directions toward fixtures arranged in different directions from a centrally located receptacle.
While particularly shown and described in the form of a four outlet receptacle, it will be apparent that aspects of the invention such as the conductive plate configuration on which the internal contacts are supported may be advantageously utilized in receptacles having other numbers of outlets.